DNA Is Not Destiny When It Comes To Heart Risk

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Posted on 11/14/2016

You can't choose your parents, so you can't help it if you're born with genes that increase your risk of heart disease. But a study finds that you can reduce that risk greatly with a healthful lifestyle.

Scientists have been wondering whether that's the case. To find out, one international consortium looked at data from four large studies that had isolated genetic risk factors for heart disease.

They identified genetic markers that seem to put people at nearly twice the risk for heart disease.

The scientists then dug further into their data to look at behavior that helps the heart, as well as at the influence of obesity. Specifically, they looked at smoking habits, obesity, diet and exercise. People who were healthy — based on at least three of those criteria — were considered, for the purposes of the study, to be following a healthful lifestyle.

The scientists were pleased to discover that the benefits of those good habits were strong, even for people who carried genetic traits that raised their risk. (Healthful habits actually benefited everyone, regardless of inherited risk.)

People with unlucky genes, heart-wise, but good health habits were half as likely to develop coronary artery disease as those with unlucky genes and an unhealthful lifestyle, according to the study.

The New England Journal of Medicinepublished the results online Sunday to coincide with a presentation of the findings at the American Heart Association's scientific sessions in New Orleans.

"At least for heart attack it's pretty clear that DNA is not destiny," senior author Dr. Sekar Kathiresan, who heads the Center for Human Genetic Research at Massachusetts General Hospital, told Shots. "You have pretty good control over your own health."

Kathiresan and colleagues in the United States and Sweden based their conclusion on four big studies, involving more than 55,000 people. Two of those studies have been following people for more than 20 years, including the Atherosclerosis Risk in Communities study in the United States, and a similar study in Sweden.

People with unlucky genes were at about twice the risk of getting heart disease as a group, the scientists found. But those with healthful habits basically cut that risk in half.

Participants in the study who had an increased genetic risk and poor health habits had a 10 percent chance of having a heart attack or similar event over the course of 10 years. And those with unlucky genes and good health habits had a 5 percent chance.

That 5 percent risk was within the same ballpark of many people who had a comparatively good genetic profile, Kathiresan told Shots.

The genetic test of heart risk that the researchers used "is not a test that a physician can order," he said. But materials published online along with the paper identify approximately 50 gene variants that, collectively, increase a person's risk of heart disease. And if you're determined to see how you rank in terms of genetic risk relative to the general population, a test from 23 and Me does scan these genes.

Alternatively, Kathiresan said, you can assume you may have inherited a risk factor for heart disease if a parent or a sibling died young as a result of heart disease.

One limitation of this study, the scientists note, is that most of the participants were white, so the results may not apply to every group. Researchers hope to soon expand their research to include a more racially diverse population.